3-(halophenyl)-1, 1-dialkyl ureas and weed control compositions and methods



Patented Oct. 13, 1953 1 UNITED STATES PATENT OFFICE 3- (HALOPHENYL)-1,l-DIALKYL AND UBEAS WEED CONTROL COMPOSITIONS AND METHODS Charles w.Todd, Wilmington,

E. L du Pont de Nemours 8: Company, Wilmington, M, a corporation ofDelaware No Drawing. Application February Serial No. 271,631

DeL, aleignorto 8 Claimm, (Cl. ll-2.8)

where A is a secondary amino radical selected from methylpropylamino,methylbutylamino and diethylamino radicals, X and Z are selected fromhydrogen and halogen, and Y is selected from hydrogen, halogen, alkyl,or alkoxy, the alkyl radical in said alkyl and alkoxy substituentscontaining up to four carbon atoms, and at least one and at most two ofX, Y, and Z being halogen.

Y in Formula 1 above is preferably hydrogen, chlorine, methyl, ethyl, ormethoxy,'and halogen substituents on the benzene nucleus are preterablychlorine.

The herbicidally active compounds of the invention are prepared by thereaction of an appropriate monoor dihalo-substituted phenyi isocyanatewith a secondary amine selected from methylpropylamine,methylbutylamine, and iiiethylamine, the propyl or butyl radicals of theamines in said group being either straight or branched .chain. Thefollowing equation showing specific reactants illustrates the reaction:

omQNco HN(CHI)CIH1 The amine-isocyanate reaction is most readily carriedout in the presence oi an inert solvent,

2 such as, toluene, anisole, benzene, chlorobensene, or dioxane. Nocatalyst is needed, and since the reaction is exothermic it isordinarily unnecessary to supply heat. Thus the reaction is convenientlycarried out by first mixing the isocyanate with the inert solvent atroom temperature and then gradually adding the secondary amine reactantwhile permitting the temperature to increase thru the range 0! say 25 toC. The tri-substituted urea products are generally quite insoluble inthe solvent used and, therefore, precipitate out as tormed and arereadily separated from the reaction mass.

The halophenyl dialkyl ureas oi the invention 1 are white crystallinesolids. They are insoluble or only slightly soluble in water and coldbenzene and, in general, appreciably soluble in dioxane, acetone,ethylacetate, ethanol, and hot benzene.

The halophenyl isocyanates used as starting materials can be prepared bythe general method described in the literature [Vittenet, Bull., Soc.Chim. 3 21, 588, 954 (1899); Organic Synthesis.

Collective, vol. II, page 453; and U. S. Patent 2,428,843] whichconsists in heating the haloaryl carbamyl chloride first obtained bytreating the haloaryl primary amine with phosgene at ordinarytemperature in the presence 01 an appropriate solvent or reaction media.

Illustrative oi the herbicidally active compounds of the inventionrepresented by Formula 1 above are:

3- (p-chloropheml) -1-methyl-l-isopropylurea 3 (m fluorophenyl) 1 methyli isopropylurea 3 (m chlorophenyl) 1 methyl 1 isopropylurea 3 (pbromophenyl) 1 methyl 1 isopropylurea a-(p-iodophenyl)-1-methyl-1-isopropylurea 3 (3 bromo 4 chlorophenyl) 1 methyl 1isopropylurea I 3 (3.5 dichloro 4 methoxyphenyl) l methyl 1isopropylurea 3- (p-chlorophenyl) -1-methyl-1.-n-

butylurca 3 (m --chlorophenyl) 1 methyl- 1 nbutylurea 3 (3.4dichlorophenyl) 1 methyl l n butylureaB-(S-chioro-p-tolyl)-1-methyl-i-n-.-

butylurea 3 (3,4 dichlorophenyl) 1 methyl 1 isopropylurea3-(3-chloro-p-tolyl) -1-methyl-1-isopropylurea 3 (3.5 dichloro p tolyl)1 methyl 1 isopropylurea 3- (3-bromo-p-tolyl) -1-methyl-1-isopropylurea3 (p chlorophenyl) 1,1 dietlrylurea 3 (m fluorophenyl) 1,1 diethylurea 3(m chlorophenyl) 1,1 diethylurea 3 (p bromophenyl) 1,1 diethylurea 3 (pbromophenyl) 1 methyl 1 sec.

butylurea 3 (p chlorophenyl) 1 methyl 1 tert.

butylurea 3 (3,4 dichlorophenyl) 1 methyl 1 tert.

butylurea 3 (m chlorophenyl) 1 methyl-1-n-propyl--v urea 3 (pbromophenyl) 1 methyl 1 n propylurea 3 (p iodophenyi) 1 methyl 1 npropylurea 3 (3.4 dichlorophenyl) 1 methyl 1 n propylurea 3-(3-chloro-p-tolyl) -1-methyll-npropylurea 3 (3 chloro 4 ethylphenyl) 1methyl 1 isopropylurea 3 (3 chloro 4 isopropylphenyl) 1 methyl 1isopropylurea 3 (3 chloro 4 sec.butylphenyl) 1 methyl 1 isopropylurea 3(p chlorophenyl) 1 methyl 1 isobutylurea 3 (m chlorophenyl) 1 methyl lisobutylurea 3 (3,4 dichlorophenyl) 1 methyl 1 isobutylurea 3-(3-chloro-p-tolyl) -1-methyl-1-isobutylurea 3 (p iodophenyl) 1,1diethylurea 3 (3,4 dichlorophenyl) 1,1 diethylurea 3 (3 chloro p tolyl)1,1 diethylurea 3 (3.5 dichloro p tolyl) 1,1 diethylurea 3 (3 chloro 4ethylphenyl) 1,1 diethylurea 3 (p chlorophenyl) 1 methyl 1 sec.

butylurea 3 (m chlorophenyl) 1 methyl 1 sec.

butylurea 3 (3,4 dichlorophenyl) 1 methyl 1 sec.

butylurea 3- (3-chloro-p-tolyl) -1-methyl-1-sec.

butylurea 3 (3 chloro 4 methoxyphenyl) 1 methyl 1 isopropylurea 3 (3chloro 4 isopropoxyphenyl) l methyl 1 isopropylurea 3 (p chlorophenyl) 1methyl 1 n propylurea 3 (m fluorophenyl) 1 methyl 1 n propylurea Forapplication of the herbicidally active compounds of the invention, thecompounds are preterably admixed with a carrier material or conditioningagent of the kind used and referred to in the art as a pest controladjuvant or modifier in order to provide formulations adapted for readyand efficient application to soil, weeds, or'

unwanted plants using conventional applicator equipment.

Thus, one or more of the herbicidally active compounds of the inventionare admixed with carrier or adjuvant materials to provide iormulationsin liquid or solid form. For example.

herbicidally active compounds with a non-solvent carrier which may beeither solid or liquid.

Thus, herbicidal dust compositions are compounded to givehomogeneoustree-flowing dust by admixing the active compounds with finely dividedsolids, preferably, tales, natural clays, pyrophyllite, diatomaceousearth, and flours such as walnut shell, wheat, red wood, soya bean, and

cottonseed flours. Other inert solid carriers which can be used toprepare the herbicidal iormulations include magnesium and calciumearbonates, calcium phosphate, sulfur, lime, etc. either in powder orgranular form. The percentage by weight oi the essential activeingredients will vary according to the manner in which the compositionis to be applied but, in general, will be 0.5 to by weight of theherbicidal composition.

Liquid herbicidal compositions can contain, for example, one of theactive herbicidal compounds of the invention dispersed in water or othernonsolvent carrier. To secure such homogeneous dispersions, asurface-active agent is used. In

fact, the preferred herbicidal compositions or this invention whether inliquid or in solid form contain the herbicidally active compoundhomogeneously admixed with a surface-active agent sometimes referred toin the art as wetting, dispersing or penetrating agents. These agents,which will be referred to hereinafter more simply as suriace-activedispersing agents, cause the compositions to be easily dispersed inwater to give aqueous sprays which, for the most part, constitute adesirable method of application.

The surface-active dispersing agents employed can be oi the anionic,cationic or nonionic type and include, for example, sodium and potassiumoleates, the amine salts of oleic acid such as morpholine anddimethylamine oleates, the sulfonated animal and vegetable oils such assulionated fish and castor oils, sulfonated petroleum oils, sulfonatedacyclic hydrocarbons, sodium salt of lignin sulfonic acid (goulac),alkylnaphthalene sodium sulionate, sodium salts of sulionatedcondensation products of naphthalene and formaldehyde, sodium laurylsulfate, disodium monolauryl phosphate, sorbitol laurate,pentaerythritol monostearate, glycerol monostearate, diglycol oleate,polyethylene oxides, ethylene oxide condensation products with stearylalcohol and octylphenol, polyvinyl alcohols, salts, such as the acetate01 polyamines from reductive amination of ethylene/carbon monoxidepolymers, laurylamine hydrochloride, laurylpyridinium bromide,stearyltrimethylammonium bromide, cetyldimethylbenzyl ammoniumchloride,- lauryldimethylamine oxide, and the like. Generally, thesurface-active agent will not comprise more than about 5 to 15% byweight of the composition, and in certain compositions the percentagewill be 1 or less. Usually the minimum lower concentration will be 0.1%.

The herbicidal compositions of the'invention can also have incorporatedtherein oils, fats or similar vehicles such as cottonseed oil, oliveoil, lard, paraflin oil, hydrogenated vegetable oils, etc. Adhesivessuch as gelatin, blood albumin, resins, for example, rosin, alkyd resinsand the like, can also be used in certain compositions to liquids suchas turfural, methanol, isopropanol,

isobutanol, xylol, cresol, cyclohexanone, acetone, methyl ethyl ketone,kerosene, trichloroethylene, dimethylformamide, dimethylacetamide,alkylated naphthalenes, and the like. Such compositions are readilydispersible in water and provide excellent aqueous herbicidal sprays forfield application. The proportion of surface-active dispersing agent tourea can be 0.1 to 100% by weight in these water-dispersible herbicidalcompositions.

The herbicidal compositions are applied either as a spray or a dust tothe locus or area to be protected from undesirable plant growth,commonly called weeds, 1. e., plants growing where they are not wanted.Such application can be made directly upon the locus or area and theweeds thereon during the-period of weed infestation in order to destroythe weeds, or alternatively, the application can be made in advance ofan anticipated Weed infestation to prevent such infestation. Thus, thecompositions can be applied as aqueous foliar sprays but can also beapplied as sprays directly to the surface oi the soil.

Alternatively, the dry powdered composition can be dusted directly onthe plants or on the soil. For some purposes, as in the treatment ofponds and lake bottoms, it will be convenient to use a pellet form ofthe composition.

The active ingredients are. of course, applied in amount sufficient toexert the desired herbicidal action. The amount of herbicidally activecompounds present in the compositions as actually applied for destroyingor preventing weeds will vary with the herbicidal activity of the activeingradients, the purpose for which the application is being made (i. e.,whetherfor short term or long term control), the manner of application,the particular weeds for which control is sought, and like variables.Certain of the specific examples to follow will illustrate various kindsand amounts of application and the results obtained thereby. In general,the herbicidal compositions as applied in the form of a spray or a dustwill contain from about 0.02% to 95% by weight of herbicidally activeingredient.

The class of herbicidally active compounds 0! this invention hascharacteristics which make the compounds especially valuable frherbicidal uses. In application to soil, they a e eflective at lowdosage for control of weeds wit out damage to deep-rooted crop plants.They act to kill the weed seedlings which germinate near the surface ofthe soil before the weeds have had time to de velop a deep root system.

The solid and liquid compositions described and employed herein forapplication of the essential active herbicidal ingredient all have thecommon property of permitting application of the herbicidal compositionsthrough suitable jets, nozzles, or spreaders adapted to the handling ofgranular materials onto the plants being treated and will, forconvenience, be designated as "fluent carriers. The fluent carriers withwhich this invention is primarily concerned are non-solvent fluentcarriers.

In another method of application for weed control, the ureas areincorporated with fertilizers to form either powdery or granularherbicidal compositions thatcan be used in. the cultivation ofagriculturalcrops.

In order that the invention may be better understood, the followingexamples are given in addition to the examples already given above. Theexamples illustrate typical compounds of the in-. vention, ,methods fortheir preparation, herbicidal formulations employing such compounds,herbicidal applications, and the results obtained.

EXAMPLE 1 To a stirred solution of 36.5 parts of diethylamine in 258parts of dry dioxane was added dropwise 77 parts or p-chlorophenylisocyanate with the evolution of heat. The temperature was maintained at-30 C. After cooling the reaction mixture to 15 C., the solid, whitecrystalline product which separated was filtered and dried in a vacuummm.) oven at C. The 3-(pchlorophenyl)-1,1-diethylurea thus obtainedmelted at ll6.5-117 C. and amounted to 80 parts. A second crop of theabove urea, melting point 116-117 C., was obtained by pouring the:filtrate into 500 parts of water, and filtering and drying the resultingprecipitate. The combined yield amounted to 98 of the theory.

Analysis calcd. for CuHrsClNzO: C, 58.40; H, 6.68. Found: C, 58.19,58.45; H, 6.73, 6.72..

EXAMPLE 2 A solution of 500 parts of p-chlorophenyl isocyanate in 102parts of dry dioxane was added dropwise to a stirred solution of 262parts of diethylamine in 507 parts of dry dioxane at a rate suiiicientto produce refluxing from the heat liberated in this exothermicreaction. After the addition was completed, stirring was continued untilthe temperature of the reaction mixture had dropped to 25 C. The whitecrystals which had separated were filtered, washed with water and driedat 50 C. in a vacuum (30 mm.) oven. The first crop or 3-(p-chlorophenyl) -1,1-diethy1- urea melting at 116.5-117 C. amounted to 596parts. A second crop of 116.8 parts of this urea, melting point 15.5-l16C., was obtained on pouring the filtrate into 2,000 parts of water and.filtering and drying the resulting precipitate.

EXAIVIPLE 3 Methyl-n-propylamine (18.2 parts by weight) was added slowlywith stirring to a solution of 38.4 parts by weight of m-chlorophenylisocyanate in parts by weight of toluene at room temperature. Themixture was heated to reflux temperature and maintained at that tem-EXAMPLE 4 Methyl-n-butylamine (21.8 parts by weight) was added graduallywith stirring to 38.4 parts by weight p-chlorophenyl isocyanate in 150parts by weight toluene at room temperature. The mixture was heated toreflux temperature and maintained at that temperature for thirtyminutes. On cooling, white crystalline 3-(p-chlorophenyl)-l-methyl-1-n-butylurea precipitated and was separated and dried. Theyield was 50.3 parts by weight (83% of theoretical) M. P. 116- 7Analysis calcd. for CnHnClNnO: N,11.64. Found: N, 11.58.

Additional examples of the herbicidally active compounds of thisinvention prepared according to the foregoing methods are given in thefollowing table:

Reactants Name of Compound Isocyanate Amine m Fluorophenyl Example3-(muoroph enyl) -l, 1 diethylurea M.7P. 90.5-91.0 0., yield 8 .5 Calcd.(or CuHuFNzO: C,

62.90, H, 7.20. Found: C, 62.89; H, 7.33. Example 6:

S-(m-chlorophenyD-l, l-diethylurea.

89.5-90.0 0., yield Calc d for m igsomm c,

58.35; H, 6. Found: C, 58.01; H, 6.50.

urea.

M. P. 121 0., yield 81%. Galc'd. for ounuermo;

C, 48.75; H, 5.58. Found: C, 48.85; H, 5.57. Example 8:

ii-(p-iodophenyD-l, l-diethylurea.

M P. ll8.0118.5 0., yield 99%. C810. for C11H1IN1OI O,

41.50; H, 4.75. Found: C, 41.68; H, 4.84. Example 9:

3- (m-chlorophenyl)- 1 methyl-1- n-butylurea yield 83%.

m- Chlorophenyl.

p- B romophenyl.

p-Iodophen- Me Hi y l-n-butylamine.

m- G hlorophenyl.

Calc'd. for uHnClNzO:

Found: N, 11.63.

EXAMPLE 10 Dust formulations The following compositions are adapted fordirect application as dusts for the destruction or prevention of weedsusing conventional dusting equipment. The dusts are made by blending ormixing the ingredients and grinding the mix to give compositions havingan average particle size less than about 50 microns.

3 (p chlorophenyl) 1 methyl 1 isopropylurea 20 Talc I 80 B 3 (3 -'chlorop tolyl) 1 methyl 1 sec.butylurea 5 Cottonseed oil 4 Walnut shell flour91 I EXAMPLE 11 Water-dispersible powders The following powderedcompositions are adapted for dispersing in water for application as aspray for the destruction and prevention of weeds. The powderedcompositions are made by intimately mixing the listed ingredients usingconventional mixing or blending equipment and then grinding the mixtureto give a powder having an average particle size less than about 50microns.

Diethyl 3 (3,4 dichlorophenyl) 1 methyl 1 isopropylurea EXAMPLE 12Oil-water dispersible powders The following powdered compositions areadapted for use in the preparation of spray compositions using either anoil, water, or a combination or oil and water as the liquid diluent. The

powders are made by mixing and grinding as in the case of the powders ofExample 10.

3 (p bromophenyl) 1 methyl 1 isobutylurea '10 Alkylated aryl polyetheralcohol (wetting and dispersing agent) Fuller's earth 28 3 (3 chloro 4methoxyphenyl) 1 methyl 1 isopropylurea 80 Ethylene oxidestearate-laurate (emulsifying agent) 4 Pyrophyllite 16 EXAMPLE 13Water-dispersible liquid compositions The following compositions are ina liquid form and are adapted for addition to water to give aqueousdispersions for application as sprays. The urea herbicides are generallyquite insoluble in most oils. Therefore, the liquid compositionsordinarily are not complete solutions but rather are dispersions ofsolid in an oil. The liquid or fluid compositions shown are prepared bythoroughly mixing and dispersingthe active compounds and conditioningagent or agents in an organic liquid diluent. s

3 (p chlorophenyl) 1 methyl 1 n butylurea 25 Long chain fatty alcoholsulfate (emulslfying agent) Goulac (dispersing agent) 3 Kerosene '70 3(3,5 dichloro p tolyl) i-,1 diethylurea 1 30 Alkylated aryl polyetheralcohol (wetting and emulsifying agent) a 3 Methyl cellulose (dispersingagent) 1 Kerosene 66 EXAMPLE 14 Granular compositions The followingcompositions are adapted for application by a means of a fertilizerspreader apparatus or similar equipment. The compositions are readilyprepared by mixing the ingredients with water to form a paste. The pasteis then extruded, dried, and ground to give the desired granular size.Preferably, the granules will be in the order of one-thirty-second toonequarter inch diameter.

3 (3,4 dichlorophenyl) 1 methyl 1 EXAIWPLE 15 EXAMPLE 16 Awater-dispersible powder made by admixing 75 parts of 3-(p-chlorophenyl)-1,1-diethylurea, 2 parts of alkylnaphthalene sodium sulfonate ("AlkanoB), 3 parts of goulac and 20 parts of clay (Attaclay) was dispersed inwater to give a 3% concentration of the urea. This dispersion wassprayed on quack grass. At the end of eleven weeks, the quack grass wascompletely killed. In a control test, an aqueous spray containing 10%sodium trichloroacetate applied to the same type of grass failed to killthe roots.

Following is a tabulation of results obtained with formulations ofvarious herbicidally active compounds of the invention. In each case,the formulation employed contained 80% by weight of the herbicidallyactive compound, 18% by weight of powdered solid diluent, and 2% byweight of wetting and dispersing agents.

Formulations of each of the compounds were dispersed in water to giveaqueous spray compositions. Each aqueous dispersion was sprayed onestablished qua-ck grass which had been cut on at ground level(one-eighth to one-quarter 'nch). The applications were made atdifferent losages or rates. The dosage in terms of pounds per acre shownin the following table was that of the herbicide-11y active compoundwhich was suflicient to effect kill of the quack grass in three months.

Example Compound $25753 3-(p-chior0phenyl)-l,l-diethylurea 36 3 (pchlorophenyl) l methyl l n 18 propylurea. 3 (p chlorophenyl) l methyl ln ,36

butylurea. 3 (m chlorophenyl) 1 methyl l n 36 butylurca.

Those skilled in the art will appreciate that other herbicidally activecompounds of the class defined herein can be prepared, formulated, and

applied in accordance with the foregoing specific examples. Thus, theforegoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations are to be understoodtherefrom.

I claim:

1. A method for the destruction and prevention of weeds which comprisesapplying to a locus to be protected, in amount sufllcient to exert aherbicidal action, a trisubstituted urea represented by the formulawhere A is a secondary amino radical selected from the group consistingof methylpropylamino, methylbutylamino and diethylamino radicals, X andZ are selected from the group consising' of hydrogen and halogen, and Yis selected from the group consisting of hydrogen, halogen, alkyl, andalkoxy, the alkyl radical in said alkyl and alkoxy substitutentscontaining up to four carbon atoms, and at least one and at most two ofX, Y, and Z being halogen.

2. A composition suitable for destroying weeds comprising a carriermaterial and, in amount sufficient to exert a herbicidal action, atrisubstituted urea represented by the formula where A is a secondaryamino radical selected flk n the group consisting of methylpropylamino,methylbutylamino and diethylamino radicals, X and Z are selected fromthe group consisting of hydrogen and halogen, and Y is selected from thegroup consisting of hydrogen, halogen, alkyl, and alkoxy, the alkylradical in said alkyl and alkoxy substituents containing up to fourcarbon atoms, and at least one and at most two of X, Y, and Z beinghalogen.

- 11 12v 3. A herbicidally active trisubstituted urea 8. A compositionof claim 2 containing a surcompound represented by, the formulaface-active dispersing agent in amount sumcient x n to impart waterdispersibiiity to the composition. CHARLES w. TODD. /C- H Y-c C-l- Ig-AReferences Cited in the tile or this patent =0 UNITED STATES PATENTS z ANumber Name Date where A is a secondary amino radical selected 0'2,039,959 Urbain 4, 1936 from the group consisting of methylpropylamino,2319343 Bane 6, methylbutylamino and diethylamino radicals, x 11 6Benn-11118 A 21. 2 and Z are selected from the group consisting of2,322,761 Lolita June 1943 hydrogen andhalogen, and Y is selected fromthe 2,341,868 mtcllcock et a1 1 4 group consisting of hydrogen, halogen,alkyl, and 2374,4185 H P 1945 alkoxy, the alkyl radical in said alkyland alkoxy 2,413,510 Jone! 1 1945 substituents containing up to fourcarbon atoms, $472,347 sexton June 1949 angels? llelast one and at mosttwo of X, Y, and FOREIGN PATENTS g aogen.

Number Country Date 4. 3-(3,4-dichlorophenyl) -l,1-diethyiurea. 3 (3,dlcmomphenyl) 1 methyl 574,995 Great Britain Jan. 30, 1946isopropylurea. OTHER REFERENCES 6- 3 dichlorophenyl) I 1 1" Thompson etBotanical t vol. n'butylm- (1946), pp. 494 and 49s.

7. 3 (3,4 dichlorophenyl) -1 methyl 1 ter, "J. chem. Soc." (London)1927, pp. sec.butylurea. 1209 to=1213.

3. A HERBICIDALLY ACTIVE TRISUBSTITUTED UREA COMPOUND REPRESENTED BY THEFORMULA